Fan-blade.



S. R. SHELDON.

FAN BLADE.

APPLICATION man MR. 30 19!].

Patented D60 18, 1917.

.ing the blades and a blade constructed in 2 5 UNITED STATES PATENT OFFICE.

SIDNEY RANDOLPH'SHELDON, OF GAL'I, ONTARIO, CANADA.

FAN-BLADE.

Specification of Letters Patent.

Patented Dec. '18, 1917.

Application filed March so, 1917. Serial m5. 158,726.

To all whom it may concern: Y

Be it known that I,-SIDNEY RANDOLPH SHELDON, of the city of Galt, in the county of Waterloo, in the Province of Ontario,

Canada, have invented certain new and. useful Improvements in Fan-Blades, of which the following is the specification.

My invention relates to improvements in fan blades and the object of the invention is to devise a fan blade so formed as to eliminate the sharp shrill noise caused by the sharp edge of the blade cutting through the air and to produce a low toned hum-- accordance with my invention mounted therein. I

Fig. 2, is a face elevation of a fragment of a fan showing a portion of the annular fan blade supporting plate broken away to exhibit the fan blade construction.

Fig. 3, is a detail of an alternatecon struction of blade.

In the drawings like letters of reference indicate corresponding parts in the various figures. a V v '1 indicates the fan .frame' comprising the back plate 2 to which the hub 3 is secured and the annular front plate 4 spaced apart from the back plate 2 and between which the fan blades 5 extend in the usual manner.

Ordinarily a fan blade is made out-of a thin metal having a comparatively sharp edge which cuts -through the air producing a sharp shrill noise. To overcome this defect I have formed the front edge ofthe loop.

fan blade with an enlarged portion 6 preferably formed loop-shaped, the free endsof the loop. being secured to the upper and lower face of the blade, from which point the loop gradually spreads outward to form a substantiall semi-circular end.

In Fig. 2, have shown the loop, portion -6 separated from' the fan' blade and at tached thereto by rivets 7 passing through the fan blade and the free ends of the Inv Fig. 3,1 I have shown an alternative construction in which the loop'is made integral with theblade, the loop being formed by a blade extension which is turned in:

,wardly, and riveted to the lower face of the fan blade. This enlargement might also be constructed by casting a strip of metal of the required form having its outer edge rounded and its inner edge recessed so as to receive the, blade edge, such recessed portion being rivetedior otherwise secured to the blade.

It will thus be seen by this construction that I have provided a blade edge which has a broad rounded outer edge portion which in cutting through the air produces a low humming tone which will merge in with the general noise of a factory and be unnoticeable and will, therefore, eliminate the disagreeable sound commonly caused by a rotating fan.

What I claim as my invention is. 1. A high speed fan blade having its forward edge provided with a loop portion presenting .a rounded cutting edge. I

2. A high speed fan blade comprising a loop mem er extending from end to end of the forward edge of the blade and suitably secured thereto.

SIDNEY RANDOLIH SHELDON.

I Witnemes: G. T. OLINs,

A. P. WELLAND. 

